Triphenylphosphine → Tert-butyl 4-(4-chloro-1H-pyrazolo[3,4-D]pyrimidin-1-YL)piperidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a flame dried round bottom flask under N2 was added 4-chloropyrazolo[3,4-d]pyrimidine (J. Am. Chem. Soc. 1956, 78, 784) (1.80 g, 11.65 mmol), t-butyl 4-hydroxy-1-piperidinecarboxylate (2.46 g, 12.23 mol), and PS—PPh3 (9.21 g, 1.77 mmol/g) in anhydrous tetrahydrofuran (200 mL). The mixture was cooled to 0° C. and diethyl azodicarboxylate (DEAD) (2.20 mL, 13.98 mmol) in tetrahydrofuran (20 mL) was added dropwise. The mixture was allowed to warm to room temperature and stirred overnight. The reaction was then filtered and taken up in methylene chloride. The insoluble material was filtered off. The filtrate was concentrated, taken up in methylene chloride, and put in the freezer for 5 hr. The crystals that formed were filtered off and the filtrate was purified by silica gel chromatography (0-2% methanol/methylene chloride) to give pure tert-butyl 4-(4-chloro-1H-pyrazolo[3,4-d]pyrimidin-1-yl)piperidine-1-carboxylate. 1H-NMR (500 MHz, CDCl3) δ 8.76 (s, 1H), 8.16 (s, 1H), 4.92-5.02 (m, 1H), 4.32 (br s, 2H), 2.97 (br s, 2H), 2.20-2.31 (m, 2H), 1.96-2.05 (m, 2H). LRMS m/z (M+H) Calcd: 337.13, found: 338.09.

Provenance & Evidence